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Gayle J T Pauer, Vera L Bonilha, Mary E Rayborn, Brent A Bell, Meghan J Marino, John R Heckenlively, Elias I Traboulsi, Stephanie A Hagstrom, Joe G Hollyfield; Retinal Histopathology in Eyes from a Carrier of XLRP with an RP2 Mutation. Invest. Ophthalmol. Vis. Sci. 2014;55(13):6338.
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© ARVO (1962-2015); The Authors (2016-present)
To describe the histopathological features of donor eyes from a carrier of X-linked retinitis pigmentosa (XLRP) with an RP2 mutation.
Eyes were obtained from a 90 year-old and fixed within 25 hours postmortem. Globes were evaluated with macroscopy, SLO and OCT imaging. Perifoveal and peripheral retina were processed for electron microscopy and immunocytochemistry using cell-specific antibodies. Three age-matched normal eyes were used as controls. Genetic testing was performed on the family using sequence analysis. The donor was reported to have a macular dystrophy late in life. Therefore, her DNA was also genotyped for the high risk AMD SNPs rs1061170 (CFH), rs10490924 (ARMS2, rs11200638 (HTRA1, and rs2230199 (C3), using TaqMan SNP genotyping assays.
Genetic analysis identified a heterozygous 2 bp insertion in the RP2 gene, c.77insCA. She was heterozygous at the CFH Y402H and C3 R80G sites and homozygous for the non-risk alleles at the A69S ARMS2 and promoter HTRA1 sites. The fovea and optic nerve could be clearly identified by all imaging modalities. IR and red free-SLO identified hyper-reflective lesions adjacent to the macula and optic disk. OCT identified these lesions as retinal deposits, extending from the RPE to the OPL. Histology of the peripheral retina showed a distinct GCL, INL, and ONL. Patchy areas of photoreceptor loss associated with gliosis were noted in the retinal periphery. Prominent GCL and INL were present in the perifoveal retina in addition to gliosis associated with a fibrovascular scar. A serous detachment was present near the fovea, containing material stained with toluidine blue, except proximal to the RPE where blister-like projections were visible along the apical surface. Patchy, highly disorganized cells labeled with cone opsin and cone arrestin antibodies were present in the perifovea; however, cone-specific labeled cells appeared normal in the periphery. A few disorganized cells labeled with rhodopsin antibodies were detected in the perifovea but were more abundant and rod-shaped in the periphery.
The histopathological features identified in this donor, including the loss of photoreceptors in the peripheral retina, indicate the retinal degeneration is likely due to XLRP. Although the genetic screening suggests a low risk of developing AMD, the fibrovascular scar indicated a previous hemorrhage followed by fibrosis consistent with wet AMD.
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